Avalanche Forecast

Issued: Jan 31st, 2015 3:00PM

The alpine rating is moderate, the treeline rating is moderate, and the below treeline rating is low. Known problems include Wind Slabs, Persistent Slabs and Deep Persistent Slabs.

matt.mueller, Alberta Parks

Kananaskis.

With the new low density snow, loose dry avalanches are a concern in steep areas. Particularly for ice climbers in gully features and skiers in steep confined areas.

Summary

Confidence

Fair - Intensity of incoming weather systems is uncertain on Tuesday

Weather Forecast

The NW flow will bring a few flurries with little accumulation. Ridge top (2500m)winds will hit the 30km/hr mark late this evening. Meanwhile valley bottom winds will remain light. Temperatures will rise to -10 in the alpine and hover there for the next 24hrs. It will be important to watch the wind patterns as the new snow is ready to be redistributed into windslabs.

Avalanche Summary

Numerous small loose dry avalanches were seen today. Most of them were in steep, cliff terrain and didn't run as far as expected. There was one notable slab avalanche: Sz 2, E asp, 2200m alpine start zone, steep rocky terrain and a re-loaded bed surface from the last cycle.

Snowpack Summary

There was more new snow than expected overnight Friday. Amounts averaged 9cm's within the forecast region. This snow came in with light winds and reasonably cold temps. So far the wind has not created widespread storm slabs. The surface hoar noted in the past few days has now been buried. It was noted yesterday that in some open, sunny areas the sun was able to melt the surface hoar. It is thought to still exist up to treeline elevations, shady aspects and open areas. Not an immediate concern, but something to watch for down the road. The new snow appears to have not bonded well to the hard windslabs. Loose dry avalanches were common today, which suggest the poor bond will be a problem. The deeper layers are unchanged in the last while. The Dec 13 crust is down 25-35 cm's and still very apparent, but starting to break down in some areas. The Nov 6th crust/depth hoar is just off the ground, and in places completely broken down to depth hoar. Snow depths range from 68cm's at valley bottom to 151cm's at upper treeline

Problems

Wind Slabs

This problem can be divided into two categories. The first will be new windslabs, and the second will be the buried windslabs that compose the upper third of the snowpack. The new windslabs will be more concerning as the hardslab interface is poor.

Avoid freshly wind loaded features.>Caution in lee and cross-loaded terrain near ridge crests.>Caution around convexities or areas with a thin or variable snowpack.>

Aspects: North, North East, East, South East, South.

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 3

Persistent Slabs

Upper treeline is the likely place to find this problem. Very steep (40 degree+) terrain with variable coverage should be treated with caution.

Choose well supported terrain without convexities.>

Aspects: All aspects.

Elevations: Alpine.

Likelihood

Unlikely - Possible

Expected Size

1 - 3

Deep Persistent Slabs

The basal layers are still considered a weak link in the snowpack. It is becoming less of a problem as the slabs above it tighten up, but in the right terrain it is still possible to trigger it. Potential large triggers should also be assessed.

Be aware of the potential for full depth avalanches due to deeply buried weak layers.>Be aware of thin areas that may propogate to deeper instabilites.>

Aspects: North, North East, East, South East.

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

2 - 5

Valid until: Feb 1st, 2015 2:00PM